1. Field of the Invention
The invention relates to captive panel fastener assemblies; and, more particularly, to an improved fastener assembly for aircraft for holding the head and shank of the bolt of the fastener assembly away from an aperture in an aircraft panel in a first position while permitting the bolt to be pushed to a second position where the head abuts against the aircraft panel and the shank enters the aperture in the aircraft panel for subsequent connection to a mating receptacle assembly mounted to a sub-structure of the aircraft.
2. Description of the Prior Art
Panel fasteners for aircraft are well known. Usually, such fasteners secure a panel to an aircraft by insertion through an opening in the aircraft panel and a receptacle attached to the panel on the blind side is threaded to the shaft of the fastener, the enlarged head abutting against the panel on the access side thereof. Means have been suggested in the prior art for preventing the fastener from becoming disengaged from the panel when the fastener is threaded out of engagement with the receptacle.
In certain applications, the panels may be made of composite materials and such materials may be easily cracked or delaminated if the load on the panel fastener assembly is not distributed over the area surrounding the hole.
In Gulistan U.S. Pat. No. 4,285,380, a panel fastener is disclosed having a stud nut with an internally threaded bore mounted to a grommet assembly installed in a panel. The nut is adapted to threadably engage a threaded nut mounted to a subpanel. In one position, the nut is held outwardly away from the panel by a retaining ring in the grommet assembly trapped in a groove adjacent the nose of the nut. When the nut is pushed inwardly of the panel, the retaining ring in the grommet assembly rides over the shank of the nut until it abuts against the nut head thereby holding the nut to the panel in an inward position until the nut is pulled away from the panel. The ring then rides along the nut shank until it re-enters the groove adjacent the nose of the nut.
Obviously, the grommet assembly of Gulistan requires a number of carefully machined parts and a relatively thick panel 16 for installation. Gulistan also requires a rather intricate hole to be formed in the panel for the grommet assembly.
In Dey U.S. Pat. No. 4,324,517, a panel fastener assembly is disclosed for joining a panel to a sub-panel. This assembly shows a nut having an internal thread fixed to a grommet assembly installed in the panel. A receptable assembly is attached to the sub panel. The grommet assembly has a retainer ring which engages a groove in the nut body when the nut is in the outwardly extended or withdrawn position and disengaged from the receptacle assembly. As can be seen in FIGS. 5 and 8 of Dey, a number of carefully machined parts make up the panel fastener assembly. Further, as can be seen in FIG. 1 of Dey, a relatively thick panel 4 is required for installation of the grommet assembly.
Thus, in both Gulistan and Dey, a number of parts are required which must be carefully machined and sub-assembled. The sub-assemblies require a relatively thick panel for installation and add weight to the installation. Certain panels, such as car door panels and the like, must be relatively thin and are light in weight. Thus, any fastener assemblies used in such panels must be very small and light weight. The installations of Gulistan and Dey are thick and heavy and add to the weight of the installation. This is highly undesirable, particularly in aircraft installations where it increases the payload of the aircraft.
There is thus a need for a panel fastener assembly which can fasten a panel to a sub-panel where the bolt thereof may be held in a withdrawn or outward position without disengagement from the panel until it engages a fastening member, such as a stud, on the subpanel. Such a fastener assembly should be light weight, be comprised of relatively few parts, be easily manufactured and installed yet provide strength and rigidity to the installation.